My previous session ended with a cliffhanger, after the plans of the players for the Battle of Albridge had been betrayed, and the enemy had circumvented their carefully laid trap. So this session started with an enemy army 1 hour march away, and the players having to come up with a plan B on how to organize the villagers and their elven allies. Fortunately they had a good idea: They moved their troops out of the village towards the enemy, and hid behind low hills in bowshot range of the road, forming a battle line parallel to the road. When the enemy came down marching the road, the elves stepped up the hill and started firing their bows at the enemy troops. The villagers then stepped in front of the elves to protect them from the counterattack.

That plan worked quite well, as there were 150 enemies, all just regular mercenary troops. The players had 60 elven archers, 150 villagers (equipped with decent weapons and armor from a raid on a supply caravan), and the element of surprise.

But now we go from telling a story to a meta-gaming subject: Dungeons & Dragons doesn't have good rules to simulate a battle between 150 mercenaries and 210 rebels. You *can* make up such rules, for example grouping X soldiers together and handling them as 1 unit. But the result is never really satisfying: It will always be just a battle between NPCs, with rules problems if you let the players fight in the same battle. And with D&D combat rounds being just 6 seconds long, you can't have a battle raging on for an hour, and 1-minute large battles feel weird. Thus the adventure module went for a very different solution, moving the large battle into the background, and having the player play a series of skirmishes to focus on their contribution to the battle. I liked the idea, and just modified the skirmishes to be more "battle-like".

The players knew to expect about 200 enemies, and the large battle had only 150 of them. So at the start of the battle they received a message from a scout that a smaller troop of around 20 enemies was coming from the north. They sent 20 villagers to protect the village, but soon after received a second message that there was a devil with the other enemy troops, and they were burning the village. Thus they left the larger battle to focus on the threat to the village.

The enemy in the village was 20 regular troops (minions with 1 hitpoint), a mage, and a tar devil. I had originally foreseen this battle on a free battlefield, but now I used a map of a village I fortunately had brought with me. The enemy soldiers had an ability which increased their defenses if they were adjacent to each other, so they basically formed a Roman turtle to attack the players, 4x5 soldiers large. The players at first cleverly delayed their turns to give the cleric and warlord opportunity to cast their buffs (+2 on everybody's armor class, +8 temporary hitpoints). After that the first player having initiative was the dwarven fighter, who did what every dwarf would do when seeing 20 soldiers advancing towards him: He charged them! :)

Unsurprisingly the most effective player in this situation was the wizard, with his fire specialization and area effect spells. His first 3x3 column of flames took out 8 soldiers, well above average. The enemy mage on the other hand, who also had an area effect spell, could never catch more than one player with it, as the players had dispersed to avoid just that. The tar devil posed some danger, catching the ranger in a net and attacking her while immobilized. But ultimately the good tactics of the players made the combat an easy win.

A short rest later the players heard combat noises from the south of the village, where they had initially built a barricade close to the bridge and where the 20 villager troops had fled to from the devil. When the players arrived those villager were dead, with another enemy detachment consisting of 10 crossbowmen, with a leader and a spitting drake, now removing the barricades. A battle around the bridge ensued. The crossbowmen also were minions, but they didn't stand conveniently together and were a bigger threat due to their ranged attacks. Nevertheless the players did very well, for example with the ranger using an action point to dispatch 4 crossbowmen with 2 twin strikes. The enemy leader had a lot of hitpoints, but low defenses, and wasn't very lucky with his attacks. When the mercenaries were dead and only the spitting drake was left, the warlord used his intimidation skill to make him flee.

Again the players had time for a short rest (if the DM doesn't allow those, the fights get boring with only at-will powers used), before seeing smoke from burning farms further south down the road. Moving there the players encountered more enemy troops, led by the mercenary general. But as it was getting late, we kept that battle for the next session.

I find that often in heroic fantasy the battles are best left in the background, as part of the story, and not simulated and played out move by move. It is hard to make level 3 players look like heroes in a huge battle.

Interesting way to handle the battle from the pc's viewpoint, sure. But I don't know what would happen in reality if the all the strongest heroes detach from the main body during a battle and they are seen to go away. A rout, probably. But to simulate this, a single d6 roll would do, no need for complicated rules.

Anyway, for additional heroic flavor, you could also use duels and fighting against impossible odds. This kind of stuff was written down in the story of Cu Chulainn who was the legendary Irish hero from the late bronze or early iron age. There's a lot more in that story, check it out for inspiration on what might happen on the battlefield.

Either have the players do their part in the battle (as snowlatern said), however small and just cinematise the rest or make the whole thing cinematic.

If you do the later you need to put in a fair bit of effort to make it interesting otherwise it becomes a non-event.

Our group goes out of its way to include game content that is outside the DnD rules such as acting out plays, 3d chess games, dinners where players play world leaders and such like. So we might try and Chainmail or some other wargame ruleset and adopt it to the game as needed.

We once spent 6 hours playing out a multi faction wargame in a city like this and the game is still talked about several years on.

What i always liked the idea of - more suited to very large battles though - is you cut out rectangles of cardboard or paper to represent the units in each army and the terrain of the battlefield and lay it all out.

Then you specify which unit the players are in (which might represent 1000+ guys).

The DM moves the various units around in a way that makes cinematic sense (unless one of the players is one of the generals) and when two units clash have some very simple 2D6 roll with for example 2,3 meaning one side loses badly, 4,5 losing and pushed back, 6,7,8 stalemate etc.

If the players unit is shot at during this then roll that out in D&D terms e.g. throw for each player getting three potential arrow hits.

(It should be quite difficult to die doing this as fighting in ranks means wounded players are sent to the rear.)

If and when the player unit is engaged in a melee fight then play out one section of their unit's line e.g. a 10 man row, 6 ranks deep. The position of each player in the ranks could be randomized so they may not start in the front. As soldiers are hit they either go down or move to the rear and are replaced by the guy behind them.

(This could vary by the type of unit they were a part of.)

You play this out for a fixed number of rounds with some kind of kill metric to judge success or otherwise. After 6 or 8 rounds of this if the player's unit is ahead they get +1 to their unit's next 2D6 roll in the meta battle (or -1 or nothing if it's a draw). If neither side in the meta fight wins then the process is repeated with cumulative results.

If the player unit wins then the meta battle carries on and the player's unit gets moved around as before until the battle is won or lost. If the player's side or unit loses then there may be a pursuit where the players have to escape across a board pursued by enemy cavalry - maybe involving having to drop heavy armor in the process to run away faster.

Capture or the loss of equipment could then lead to future rescues and ransoms.

Could be fun.

This could work particularly well for seiges where the players and a bunch of npcs are holding one section of a wall against multiple waves of enemies.